Journal of Advanced Manufacturing Systems

This paper represents a multivariate hybrid approach, combining Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) and Principal Component Analysis (PCA) to optimize different correlated responses during Wire Electrical Discharge Machining (WEDM) process of titanium grade 6. The response parameters selected are the average cutting speed, average Kerf width and average surface roughness (Ra). All of them have been studied in terms of pulse-ON time, pulse-OFF time, wire feed and wire tension. As indicated by Taguchi’s signal-to-noise ratio, the optimum process parameters were achieved for the desired average cutting speed, average Kerf width and average surface roughness, respectively. At last, the optimum combination of process parameters was validated by affirmation test which gave considerably improved various quality characteristics. Confirmation test outcome revealed that multivariate hybrid approach MOORA coupled with PCA was a competent strategy to decide available cutting parameters for a desired response quality for WEDM of titanium grade 6.

The main aim of this work is to propose a hybrid framework, which makes use of intelligent decision-making tools, that are gray, fuzzy, and ANFIS, to optimize the multi-performance characteristics (MPCs) of powder-mixed electrical discharge machining (PM-EDM) of tungsten carbide (WC). To perform the experimentation, four input parameters: (i) pulse-on time, (ii) current, (iii) powder concentration, and (iv) powder grain size are considered to investigate the MPCs such as material removal rate, tool wear rate, surface roughness, and micro-hardness. The proposed framework uses response surface methodology (RSM) with gray, gray-fuzzy, and gray-ANFIS approaches to obtain optimal solution and also to handle the element of uncertainty or fuzziness associated with the uncertain, multi-input, and discrete data. This method helps to generate the values of gray relational grade (GRG), gray-fuzzy reasoning grade (GFRG), and gray adaptive neuro-fuzzy inference system grade (G-ANFISG) for all the 30 experiments. Analysis of variance (ANOVA) is performed on GRG, GFRG, and G-ANFISG to identify the major contributing input parameters which may affect the MPCs. Finally, the theoretical prediction is done to verify the improvement in the performance characteristics obtained through the proposed approaches. Both the experimental and statistical results clearly demonstrate the success of proposed framework for the optimization of PM-EDM of WC alloy.

For the overweight of automatic car radiator core assembly machine crimping part, the structure was optimized and designed based on ANSYS Workbench to satisfy the double objective about reducing weight and decreasing the impact of the amount of deformation of the core assembly components. Multi-objective genetic algorithm was carried out to search the Pareto optimal solution set for optimal and design problems. It shows that the weight of crimping part reduces by 5.34% compared with the previous part, the assembly flatness of core reduces by 13.43%, and the total deformation affecting mainboard press-fit and positional accuracy of the flared reduces by 6.89%, which all meet the requirements of multi-objective optimization design.

Micropump is an integrated part of microfluidic system and is a boon to the field of miniaturization, owing to its helping hand in numerous applications mainly in biomedical, electronic cooling, fuel cells, spacecraft, etc. In this paper, an attempt is made to design and fabricate valveless pump, with active and passive valves. The actuation element used is piezowafer, piezowafer was experimentally tested and compared with simulated values from ANSYS for its peak displacement and these displacements were used to find volume pumped by pump. The pumping volumes found by experimentation are in good agreement with the simulated results. Further fabrication of valveless pump is carried out by using tool-based micromachining center which is a novel type of fabrication technique in micromachining. Through experiments, the optimum frequency of the pump was found to be 60Hz at an actuating voltage of 150V. The maximum head that a pump could pump was found to be 0.051m with pressure of 500.13Pa. The flow rate of the pump had a decreasing trend with increase in head.

Presently, parts having intricate custom-made profiles are mostly fabricated using additive manufacturing (AM) processes. It becomes an essential task to verify the accuracy of AM parts so that they meet customer’s need and requirement. In product quality control, quick error comparison of manufactured part and an original CAD model is usually laborious but still a critical issue. Noncontact inspections using 3D scanners were preferred over conventional coordinate measurements, due to the significant amount of point data capturing in very short span of time. One of the important step of the noncontact inspection procedure using the 3D scanner is the correct localization of the datum reference frame. This step would help in the effective alignment of the digitized point data. This paper takes into consideration various 3-2-1 alignment approaches and investigates their influence on the inspection results. The result provides an evidence that an incorrect description of the product reference frame can lead to erroneous estimation of actual part deviations. The results show higher distance distribution for most of the point data of third alignment as the distance distribution is influenced by the worst description of the part reference frame. On the contrary, second alignment shows least distance distribution among point data due to correct reference frame definition.

This paper presents a modular liveness-enforcing supervisory control design for scalable discrete event systems. A maximally permissive monitor-based supervisory control policy is suggested using divide and conquer paradigm. A vector-covering approach is used to minimize essential set of legal markings and first-met bad markings. Providing that modules of system interact by Enable operator, it will be proved that monitor-based supervisory control methods can be applied modularly. Then, Enable operator of Petri nets (PNs) can be used to synthesize subsystems. This algorithm is implemented by extending a graphical PN drawing and analysis tool with supervisory control analysis modules as Java codes. The experimental results show that this approach constitutes a primary step towards a hierarchical procedure that overcomes whole reachability graph computation, which is a bottleneck in deadlock preventing supervisory control policies.